The G9SB has two input types available - Inverse and Positive Common.

If you are connecting a Safety light curtain then you require the Positive Common version. This is because the OSSD outputs from the SLC are PNP type safety outputs.

If a SLC is connected to an Inverse type this will cause the relay to operate as if it has detected a fault. Inverse types require on positive and one negative signal (diverse signal types)